Papers by Keyword: Rotor Steel

Abstract: The fatigue tests with 16 hours hold time have been conducted for two rotor steels, 1CrMoV and 2CrMoNiVW at 550°C to investigate their creep-fatigue interaction behaviors, as well as those without hold time for contrast. And two life prediction methods are used to correlate the present creep-fatigue life data. It is shown that a significant reduction in fatigue life is observed with hold time in tension, and it is also observed that 1CrMoV steel exhibits a higher creep-fatigue life than 2CrMoNiVW when strain hold time is 16 hours, and 2CrMoNiVW seems to be more sensitive to hold time influence. In addition, both methods could give satisfactory creep-fatigue life predictions, but with their own limitations.

Abstract: The cleanness of 30Cr2Ni4MoV steel was researched by chemical analysis, SEM and electrolytic experiment. The results show that the large-sized inclusions in the casting is the direct reason for the product to scrap. It found that there is a increase trend of large-sized inclusions and oxygen content from VD to pouring process with a cleanness detection of smelting process. It have achieved a good effect by adopting some measures to improve steel cleanliness which includes controlling the carbon content of EAF tapping reasonablly, low melting point controlling of inclusions, extending soft blow time and optimizing the flow field of tundish. The quantity of inclusions has reduced from 38.8 per square millimeter to 16.0 per square millimeter. The oxygen content has reduced from 58 × 10-6 to 32 × 10-6, and the nitrogen contents has reduced from 85 × 10-6 to 70 × 10-6 after process improvment.

Abstract: Rotor steel 26NiCrMoV145 has been widely employed in aerospace and power industry because of its unique properties. As to this new material that used widely in important places, it is worth studying its machinability. An experiment was carried out to study the cutting forces and tool wear mechanism during high speed dry turning using multilayer Al2O3 coated carbide insert. The orthogonal test was chosen, cutting forces were measured. SEM analysis has been carried out on worn tools to determine the tool wear mechanisms. Crater wear and coating peeling could be found in every cutting speed. Flank face wear appears smooth when cutting speed increases. At last, an optimization of the cutting condition was suggested when considering of material remove rate, cutting forces and tool wear.

Abstract: Rotor steel has been widely used in marine engineering and power industry because of its high yield stress and anti-fatigue performance at high temperature. The surface integrity must be guaranteed due to severe working environment. Hence it is worth studying residual stress (RS) for its significant influence on the quality of machined part. In this paper, an effective model is built with the help of finite element method (FEM) to evaluate RS induced by machining of rotor steel 26NiCrMoV145. An adaptive mesh control is introduced in this work to avoid excessive element distortion. Johnson-Cook flow stress model is proposed to model workpiece material. Rolling process is necessary to obtain desired RS according to the performance of form-milling process. In order to validate FEM predictions, both milling and rolling experiments have been carried out. The predicted RS profiles are in reasonable agreement with the experimental ones.